12. Sake Tasting

The finished sake is then tasted at room temperature. Since there are many similarities between the two sakes, apart from the rice polishing method, we will only highlight the differences.

[Flat-polished rice with germ left intact]
Refreshing, clean and light taste.
Strong sourness.

[Spherical polished rice]
A heavy, bulging texture.
Well balanced taste.

The clean, light taste of flat-polished rice is thought to be due to the reduction of impurities. On the other hand, the acidity has become stronger. Does the rice polishing method affect the amount of acid produced by yeast? Let's look at the data of sake analyzed immediately after pressing.

*Sake Meter: Indicates the specific gravity of the sake. The higher the value, the lighter the sake, and the lower the value, the heavier the sake. *Acidity and Amino Acid Level: The higher the value, the more of each component there is.

The difference in acidity is within the margin of error and does not appear to be related to the rice polishing method. This data does not explain the reason for the strong acidity. There are some differences in sake meter readings, but this indicates the specific gravity of the sake, so it is thought to have little relationship to the acidity.

Another surprising result was that the amino acid content, which is considered to cause unpleasant flavors, was within the margin of error. However, the amino acid content only indicates the tendency of the total amount of amino acids contained in alcohol, and does not represent anything specific. As mentioned in 5 and 6 on page 2, changes in the amount of each amino acid affect the taste of alcohol. There seems to be something here. So we decided to take a closer look at the amounts of each of the 20 types of amino acids.

The high acidity of both sakes (usually around 2.5 at Taketsuru Sake Brewery) is due to the fact that Taketsuru No. 6 has acquired a tolerance to alcohol, leading to the production of large amounts of succinic acid and malic acid as by-products. The flat, spherical shape and refreshing taste are likely due in part to malic acid.

13. Amino acid content: "Umami effect"

The results are as follows. In addition to the four major amino acids listed in 5 on page 2, basic and umami components are also listed.

Amino acid composition details

(Analysis: Hiroshima Prefectural Technology Research Institute Food Industry Technology Center)

As previously reported, the reduction rate of arginine was large, and it was suggested that the clean, light taste felt when tasting the flat-polished rice was largely due to the reduction in arginine, an impurity component. Reductions in glutamic acid and aspartic acid are also thought to be contributing factors. It was surprising that the reduction rate of amino acids in "flat-polished rice with germ retained" was only about 10% overall, but it was a valuable experience to see how this alone can have a major impact on the taste of the sake.

But why does flat-polished rice have a stronger sour taste? As mentioned in 10 on page 3, umami has the effect of interfering with other tastes. For example, the bitterness of bitter melon is softened by umami. With flat-polished rice, the umami components have been reduced, so perhaps the sour taste stands out. It could also be that with spherical-polished rice, the refreshing taste of malic acid is softened by umami. Also, when asked whether there was a noticeable off-flavor with spherical-polished rice, the taste was not so strong. This is also thought to be due to the off-flavors being softened by umami.
As a result of trying sake made with flat-polished rice in order to reduce impurities, I came to realize the power of umami.

Flat polished rice with minimal unpleasant flavors

Richly flavored spherical rice

It can be said that.

The DMTS-pp at the bottom of the table indicates the potential for odor from deterioration. This was reduced by 25%, which was as expected.

14.Productization

After pressing, the sake is pasteurized and stored in tanks, where it is aged for a year and a half to bring out the rich flavor that makes it "delicious to eat" and to see the difference in the smell of deterioration. It is finally ready to be shipped. Most sake is diluted before shipping to balance it. After tasting the sake, we decided to commercialize it at an alcohol content of 16.2%, which provided the best balance of flavor.

15. Drinking temperature and malic acid: "Differences in taste depending on temperature" of malic acid

One of the characteristics of sake is that it can be enjoyed at a wide range of temperatures, from cold to warm, even if the ingredients are the same. The 12 tastings were at room temperature, but we tried it at a variety of temperatures. Spherical polished rice seems to be best balanced when served hot, and goes well with food. The umami flavor is more pronounced when the sake is warm, so this characteristic was apparent.

On the other hand, flat-polished rice has less umami, so it seems that the balance when warmed and its compatibility with food are not as good as those of spherical-polished rice. In fact, it feels a little heavy after drinking. This heavy taste is thought to be due to malic acid. Malic acid is perceived differently depending on the temperature, and while it has a refreshing feeling when cold, it has the property of becoming bitter and astringent when heated, resulting in a heavy taste. This heavy taste should also be found in spherical-polished rice, but as mentioned in 13, it is thought to be softened by the abundant umami. Rather, flat-polished rice is best served chilled to cold (in Japanese sake, "cold" refers to room temperature), taking advantage of the clean taste due to the lack of impurities and the refreshing feeling of malic acid. Even if it is heated, it should only be lukewarm.
The results showed that the difference in the amount of umami due to the rice-polishing method and the difference in taste due to temperature of the malic acid produced by the Taketsuru No. 6 yeast affect the drinking temperature.

Flat polished rice: Cold sake to lukewarm sake Spherical polished rice: Warm sake to extremely warm sake

It can be said that "Flat-polished rice with germ left in" has less umami components, but this is in comparison to other products from Taketsuru Sake Brewery, and is far richer than regular sake (amino acid content of about 1.3). We also introduce the comments of Yamamasu Sake Shop in Tottori Prefecture, which is well-known for its sake tasting.

[Flat-polished rice with germ left intact]
Golden yellow. Complex yet transparent aroma of brown sugar, orange, kumquat, kelp tsukudani, soy sauce lees, etc. The mature flavor, which is intertwined with the sourness of kumquat and orange, is smooth and transparent. When air is added, the sweetness of the matured sake and the sourness of the citrus fruits bring out the sweetness of the matured sake, and the astringency supports them, making a strong impression.
(Warm) 40%: The strong, mature flavor is well-balanced with the citrus acidity and astringency, and the acidity then cuts off cleanly. Refreshing. 50%: The mature flavor is a fusion of citrus acidity, and the very sharp acidity makes it easy to cut. The astringency tightens the sweetness.
At 60 degrees, the acidity becomes rounded and the citrus acidity blends together to create a mellow, mature flavor. The bitterness gives it an edge in the latter stages.

You can enjoy the mature taste with a touch of acidity at any temperature.

[Spherical polished rice]
Golden yellow. Mature aroma of brown sugar, red miso, kelp stock and subtle citrus aroma. The mature flavor is mixed with the smooth umami of rice koji, but when air is absorbed, the citrus acidity begins to intertwine all at once, supporting the sweetness of the matured flavor. The spiciness and astringency of the sour tail also spread. It has a more solid and soft feel than the flat sake.
(Warm) 40 degrees, the soft aged flavor of the rice koji is tightened by the acidity and astringency, and the acidity leads to a dry taste. Astringency in the aftertaste. 50 degrees, the acidity that is intertwined with the slightly stronger aged flavor becomes noticeable. When air is added, the astringency and slight bitterness give it body.
At 60 degrees, the umami of kelp stock and rice malt can be felt in the mature flavor that blends with the acidity. The acidity and astringency add a rich spiciness. I like it warmed to 60 degrees.

Although everyone has their own preferences, we encourage you to try them all and compare them for yourself.

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